I’d love to have the option of excluding certain collections from the “reading now” view. I have a few collections on my iPad containing books I’m translating, and they’re always in various states of read/partially read/unread since I page backwards and forwards looking for references, etc. They tend to clutter up the “reading now” view and push my “real” reading sessions off the page.
It’s probably not a common use case, though, so I imagine it’d be pretty far down the priority list.